Schedule Performance Index (SPI)

The Schedule Performance Index (SPI) is a metric used to measure how well a project is progressing compared to its planned schedule. It is calculated by dividing the work actually completed (earned value) by the work that was scheduled to be completed by this point. An SPI value of 1 indicates the project is on track, above 1 means it’s ahead of schedule, and below 1 shows it’s behind. It helps project managers quickly assess project progress and make informed decisions to stay on schedule.